This week I've been at the Applied Physics Laboratory at Johns Hopkins University, where I am covering the New Horizons flyby of Pluto. It's been humbling and inspiring to witness a landmark achievement in human history: the complete exploration of the classical solar system.

It says so much about the nature of space exploration that one reflexively uses the pronouns "we" and "us" when discussing it. I can think of no other peaceful human endeavor where that is the case.

We didn't map the human genome; scientists did. We did not discover the Higgs boson. Physicists get the credit. When Olympic world records are set, nobody watching from his or her couch says, "Well, it looks like we are faster now." But we went to the moon and we're looking for life on Mars. (Conversely, we invaded Afghanistan. We defeated the Nazis. We fought wars in Iraq and Vietnam. Perhaps the wonder of space exploration is the alter ego to the horror of war.)

In 2011, New Horizons discovered a second moon orbiting Pluto (Kerberos), and a year later a third (Styx). That’s been both exciting and worrying. These moons lack the mass and gravity to keep debris caused by planetary collisions from flying into space, where they could potentially smash into the spacecraft. Debris doesn’t have to be big to be a threat: a piece the size of a grain of rice could prove catastrophic to the probe. Think of a rock hitting your windshield. Now imagine if you were driving 31,000 miles per hour.

The Long Range Reconnaissance Imager, or LORRI, "is essentially a digital camera with a large telephoto telescope—only fortified to operate in the cold, hostile environs near Pluto,” according to the New Horizons team. LORRI is so powerful that on closest approach, it was able to resolve features as small as football fields. The instrument began snapping shots of the Pluto system at the start of 2015 and is responsible for pretty much every shot we’ve seen so far. The camera only takes black-and-white photographs; color filters were left out of the design in order to keep things simple, and to ensure an extremely high light-sensitivity level. (Light levels are 1000 times lower in the Pluto system than on Earth.) The Ralph instrument provides the color data for LORRI images.

We know well the way astronauts think because we've studied them for so long — lionized them, rightfully, in books and movies and on television. We understand the human adventure. We understand that astronauts train hard and while in space live in pretty miserable conditions. But we also understand the glory of being an astronaut. They are humanity's ambassadors. They are exploring the final frontier. They've played golf on the moon! But what of these people — the New Horizons people, these spacecraft pilots and planetary scientists who study the outer reaches of the solar system? What can be made of them? Alice Bowman said the words, "We are outbound from Pluto." Has a more breathtaking string of words ever been uttered?